1. Field of the Invention
The present invention relates to the field of presses, and in particular, relates to improvements within a shaft straightening press.
2. Description of the Prior Art
Shafts and heavy machinery, such as turbines, generators, and other types of heavy equipment are subjected to extremely high stresses over long operational cycles. As a result, such shafts may become bent or run out-of-true. Very often, if such a shaft is out-of-true by 5,000ths of an inch or more, it may cause excessive wear of the shaft or of other machinery, and may cause undesirable vibrations and degradation of performance of the machinery. However, such a shaft can be brought into alignment by the precise exertion of large amounts of force in a shaft straightening press.
One such press is shown by Ernst, "Shaft Straightening Press," U.S. Pat. No. 2,336,349. Presses of this type include shaft stands which are movable in a horizontal direction and include supporting blocks, which hold the shaft to be straightened during the straightening operation, which blocks are movable in a horizontal as well as the vertical direction. Ernst includes a movable carriage which can be translated down the bed of the press. An actuating ram is included within the carriage and thus can be brought to bear against the shaft where desired. However, Ernst employs a complex system using rack and pinion gearing to drive the carriage along the bed by means of rollers rolling on rails rigidly connected to the press bed. Similarly, the supporting blocks are coupled to the press bed through similar rack and pinion gearing system. The result is that a press of the type shown by Ernst is expensive to manufacture and requires continual maintenance to ensure its smooth operation. Furthermore, the movable carriage is locked to the bed only by locking the carriage to the rack and pinion gear system. This adds additional costs and complexity to the mechanism. Moreover, gearing systems are always characterised by the existence of backlash which is particularly true in the case of heavy-duty gearing systems which must bear the types of stresses found in a press of this type. Such backlash becomes further aggravated over the course of time with wear.
Therefore, what is needed is a design for a shaft straightening press which is simple to manufacture, which maintains the precision of its operation without the need for complex gearing systems, and which is not subject to substantial degradation of the precision of its operation due to normal wear and tear.